Methods and apparatus for connecting a cable network to other network and/or devices

ABSTRACT

Methods and apparatus for connecting, e.g., bridging, a cable network to other networks and/or devices is described. A bridge device facilitates the distribution of cable provider content to end users operating IP based devices. The bridge device performs one of more of the following: interface protocol conversions, user device controlled tuner selection, transcoding of data, transrating of a data stream, decryption in accordance with a conditional access protocol and re-encryption in accordance with an authorized service domain protocol.

RELATED APPLICATION

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 11/378,129, filed Mar. 16, 2006 now U.S. Pat. No.8,347,341 and the present application also claims the benefit of U.S.Provisional Patent Application Ser. No. 60/909,476, filed Apr. 1, 2007and wherein the Provisional Patent Application Ser. No. 60/909,476 ishereby expressly incorporated by reference in its entirety.

FIELD

Various embodiments relate to cable network content distribution and,more particularly, to methods and apparatus for bridging a cable networkto other networks and/or devices, e.g., IP based user devices.

BACKGROUND

A cable network provider has available a wide range of content, e.g.,video content, which is made available to its subscribers through a settop box (STB) interface coupled to specific types of display devicessuch as a television or video recorder which accommodate the videooutput format of the STB. With the proliferation of different types ofIP based user devices supporting video/audio capabilities, there is aneed for methods and apparatus that could allow these IP based userdevices to also be coupled to a cable network and/or also be able toaccess content typically restricted to cable type video format devicessuch as set top boxes.

SUMMARY

Various embodiments are directed to methods and apparatus related tofacilitating the communication of information between a cable networkand Internet Protocol (IP) based end user devices. A bridge device inaccordance with the present invention facilitates the distribution ofcable provider content to end users operating IP based devices. Thebridge device performs protocol conversion operations. In various, butnot necessarily all embodiments, the bridging device is implementedwithout the use of a full video decoder and/or composite video outputs.In such implementations, the bridge device may be easier to implement,from a hardware perspective, then a full set-top box responsible fordecoding and outputting decoded video to another device, e.g., atelevision. In such embodiments the user device, e.g., P.C., receivingthe video may perform the decoding. In various embodiments, the bridgedevice performs one of more of the following: interface protocolconversions, user device controlled tuner selection, transcoding ofdata, transrating of a data stream, decryption in accordance with aconditional access protocol and re-encryption in accordance with anauthorized service domain protocol.

An exemplary method of providing content, in accordance with someembodiments, comprises: receiving content via a cable network; andoperating a bridging device to interface between said cable network andat least one of: i) a non-cable network and ii) an end user device. Anexemplary bridging device, in accordance with some embodiment,comprises: a cable network interface for receiving content via a cablenetwork; a second interface for interfacing said bridging device to atleast one of i) a non-cable network and ii) an end user device; and aprotocol conversion module for performing a protocol conversion betweena first protocol used by said cable network interface and a secondprotocol used by said second interface, said second protocol beingdifferent from said first protocol.

While various embodiments have been discussed in the summary above, itshould be appreciated that not necessarily all embodiments include thesame features and some of the features described above are not necessarybut can be desirable in some embodiments. Numerous additional features,embodiments and benefits of various embodiments are discussed in thedetailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 illustrate exemplary communications systems implemented inaccordance with the present invention.

FIG. 3 illustrates an exemplary bridge device implemented in accordancewith the invention.

FIG. 4 illustrates a flowchart of an exemplary method of operating abridge device in accordance with the present invention.

FIG. 5 illustrates a flowchart of an exemplary method of operating anend user device coupled to a bridge device in accordance with thepresent invention.

FIG. 6 is a drawing illustrating exemplary operations performed by abridge device, input data, intermediary data, and output data inaccordance with an embodiment of the present invention.

FIG. 7 is a drawing of an exemplary system including a bridge devicewhich performs transcoding and/or transrating operations in accordancewith the present invention.

FIG. 8 is a flowchart of an exemplary method of operating a bridgedevice, e.g., bridge device of FIG. 7, in accordance with the presentinvention.

DETAILED DESCRIPTION

FIG. 1 is a drawing of an exemplary system 100 including contentdelivery, e.g., video content delivery, to end users in accordance withvarious embodiments of the present invention. The exemplary system 100includes a novel bridge device 102 in accordance with the presentinvention. The bridge device 102 includes a cable network interface 104,e.g., video network interface, and a secondary interface 106, e.g., anIP interface. A cable network 108, e.g., a video network, includingcontent servers 110, e.g., video content servers, and control devices112 is coupled to the cable network interface 104. The cable networkinterface 104 is coupled to a standard cable connection 114, e.g., acommunity access television CATV connection, sometimes referred to as acable TV connection. The IP interface 106 couples the bridge device 102to an Internet Protocol (IP) network 116, a wireless network 111, e.g.,a Wi-FI network, and/or one or more IP based devices such as personalcomputers 118, PDAs 120, STBs 121, handheld IP devices 122, cell phones124, and/or other IP/media devices 126, e.g., IP/media capable deviceswhich support encryption. In this exemplary embodiment, the IP network116 is coupled to the IP interface 106 of the bridge device 102 via aMoCA connection and/or an Ethernet connection 128. In addition, the IPnetwork 116 is coupled to additional IP devices (IP device 1 130, . . ., IP device N 132) via an Ethernet 134. Various other IP based devices(118, 120, 121, 122, 124, 126) are coupled to the IP interface 106 ofthe bridge device 102 via a USB connection 136. Base station 115 ofwireless network 111 is coupled to the IP interface 106 of the bridgedevice 102 via an Ethernet and/or MoCA connection 113. Various wirelessdevices (PDA 117, personal computer 119, cell phone 121) of the wirelessnetwork 111 are coupled to base station 115 via wireless links (123,125, 127), respectively.

The bridge device 102 allows cable network content, e.g., video networkcontent, to be accessed and viewed using IP based user devices. The IPbased user devices such as, e.g., a personal computer 118, perform thefinal video decoding and/or display functions. The bridge device 102performs protocol conversion operations between protocols used by thecable provider network 108 to various IP based protocols used by typicalcustomer IP devices such as, e.g., personal computer 118. For example,the bridge device 102 allows a user to access content, e.g., videocontent available from a cable provider, without having to install aspecial cable modem in the user's PC. The cable network interface 104,e.g. video network interface, of the bridge device 102 and/or associatedmodules terminates cable network protocols, e.g., video networkprotocols such as e.g., conditional access (CA), industry standardarchitecture (ISA), video on demand (VOD), etc. The IP interface 106 ofthe bridge device 102 provides authorized service domain (ASD),universal plug and play audio video (UPnP AV), and other genericinterfaces to various IP devices. In some embodiments, the IP devicescoupled to the IP interface 106 of the bridge device 102 are part of atrusted domain, and the devices support encryption.

FIG. 2 is a drawing 200 of a variation of the exemplary system 100 ofFIG. 1 illustrating some exemplary signaling. The system 200 of FIG. 2also includes a High Speed Data (HSD) network 202 which is coupled tothe IP network 116. Exemplary signaling 204 between the cable network108 and the bridge device 102 includes moving picture experts group(MPEG) transports streams, e.g., MPEG2 transport streams, systeminformation (SI) and electronic program guide (EPG) data. Exemplarysignaling 206 between the bridge device 102 and IP network 116 includesuniversal plug and play (UPnP) content server signals, command andcontrol tuner resource information, and content transfer signals. TheHSD network 202 may, and sometimes does, provide signals 208 includingguide data, application download information, uniform resource locator(URL) data, etc., to the IP network 116. The guide data, applicationdownload, URL data, etc. happens through a HSD connection to thecustomer premise, e.g., home. The high speed data network 202 provides amuch larger pipe for communicating information than is typically usedfor such information with the cable network 108. A standard guide isprovided via the cable network 108; however, a specialized, e.g.,customized and interactive guide, is provided via the HSD connectionfrom the HSD network 202. Specialized service provider applicationsoftware is installed on the customer's IP device, e.g., PC.Accordingly, more detailed and/or interactive menu/guide information canbe provided when the HSD connection, e.g., via the bridge 102, suppliesmenu/guide information for the video content being supplied via thecable network 108 to an end user device. Exemplary signaling 210 is,e.g., a customized and interactive guide sourced from the high speeddata network 202 which is being forwarded to one or more of the end userdevices (118, 120, 121 122, 124, 126) via bridge device 102. Thus, thebridge device 102 provides a way of taking advantage of featuresavailable from both the cable network 108 and data network 202, e.g., ina seamless manner.

In some embodiments a resource manager within the bridge device 102handles multigroups and other content distribution functions. The mediaover coax (MoCA) distributes IP over coax. One or more streams can besent to each IP user device. In some cases, the stream may be a point topoint stream to an individual IP device. In some other cases, the streammay be a multicast stream available to a plurality of IP user devices,e.g., a plurality of IP devices coupled to the same Ethernet or localarea network. In some embodiments, the IP device, e.g., IP device 1 130which may be a PC sends channel/tuner commands and the bridge device 102implements the received commands.

The bridge device 102 provides a bridging function between the videonetwork 108 and IP devices (118, 120, 121, 122, 124, 126) at a customerpremise, e.g., home. For example, video available on cable is madeavailable on a personal computer 118, via the bridge device 102. Thebridge device 102 allows connection from a video network 108 to personalcomputers, set top box devices, personal media devices and other IPbased devices. The bridge device 102 converts, e.g., transcripts,content protection from a conditional access domain to an AuthorizedService Domain (ASD). The conditional access domain uses the currentencryption for video, while the authorized service domain usesencryption for trusted devices. Thus decrypt and re-encrypt operationsare performed by the bridge device 102, and encrypted video content onthe video network side may be converted to have different encryption onthe IP side corresponding to different end users. Other operations ofthe bridge device 102 include, e.g., performing routing of contentand/or MPEG, e.g., MPEG-2 transport streams, to the IP network. Inaddition, the bridge device routes and/or converts system informationand other information such as guide information and tier information tothe IP network 116 from the video network 108. Program guide conversionconverts an electronic cable program guide to a format which can bepresented to an IP device.

The bridge device 102 in some embodiments also supports resource poolingand home networking. An IP device typically does not have a tuner fortuning to QAM streams. In some embodiments, the bridge device 102 tunes,decrypts, and distributes to the IP network 116. The IP device decodesand displays the distributed information. The bridge device 102 hastuner capability for tuning QAM streams; however, in some embodiments,the bridge device 102 does not include decoding capability. In such anembodiment, the decoding is left to be performed in the IP network 116and/or individual IP device. This approach facilities a simpler and lessexpensive bridge device design than would otherwise be implemented ifthe bridge device also performed full video decoding operations.

FIG. 3 is a drawing of an exemplary bridge device 300 implemented inaccordance with the present invention. The exemplary bridge device 300may be the bridge device 102 of FIG. 1 or FIG. 2. The bridge device 300provides a cable, e.g., video, to IP bridge, thus bridging a cable,e.g., video network, to IP devices on a customer premise network, e.g.,a home network. The exemplary bridge device 300 is coupled to the cablenetwork through a coaxial cable 302 and provides a USB connection 304,Ethernet connection 306, Multimedia over Coax Alliance (MoCA), other IPinterface connection 305, and other PC interface connection 307 to thecustomer premise network, e.g., home network, and/or individual end userdevices. The bridge device 300 serves video streams, Emergency AlertSystem (EAS) messaging, Electronic Program Guide (EPG) data, Video OnDemand (VOD) and other interfaces from the cable network to the IPnetwork in a generic way so that the IP devices can leverage the HybridFiber-Coax (HFC) infrastructure. The bridge device 300 also bridges thecopy protection and/or additional access on the video network to theAuthorized Service Domain.

On the cable network, e.g., video network, side, there is a coaxinterface 310 which is coupled to cable network devices via coax cable302. On the IP interface side, there are a plurality of alternative IPbased interfaces, e.g., a USB interface module 312, an Ethernetinterface module 314, a MoCA interface module 316, an other IP interfacemodule 318, and an other PC interface module 320, e.g., an RS232interface module and/or an RS422 interface module, etc.

The bridge device 300 includes a tuner module or modules 322, e.g., inthe 50-1000 MHz range, an out-of-band (OOB) communications module ormodules 324, an embedded conditional access (CA) module 326, one or moremicroprocessors (uP) 328, a transcoding module 330, a transrating module332, an ASD module 334, memory 336, a power module 338, a media overcoax alliance (MOCA) interface module 316, a USB interface module 312,an Ethernet interface module 314, an additional IP interface module 318,an additional PC interface module 320, a coax interface 310, a resourcemanager module 331, a content routing module 333, a system informationrouting module 335, a program guide conversion module 337, and aprotocol conversion module 342 coupled together via one or more busses340 over which the various elements may interchange data andinformation.

In one particular exemplary embodiment, the bridge device 300 is astandalone device having the following characteristics: the device isset-top-box (STB) type device that does not include an audio/videodecoder which outputs unencoded audio/video for listening/display; doesnot include video outputs; and includes IP capable outputs includingUSB, MoCA and Ethernet. The bridge device 300 bridges video services toIP device(s). In some embodiments, the bridge device 300 includes asingle tuner, while in other embodiments multiple tuners are included.The bridge device 300 includes embedded CAS. The bridge device 300provides transcription from conditional access (CA) to authorizedservice domain (ASD). Embedded conditional access module 326 includes adecryption module 327 for decryption of received information using theconditional access protocol. In some embodiments transcoding and/ortransrating functions are included and implemented by transcoding and/ortransrating modules (330, 332). In some embodiments, the transcodingmodule 330 performs both a transcoding and transrating function.

The tuner 322 allows the bridge device 300 to tune in and receive a QAMcommunications channel. The Out of Band (OOB) Communication module 324,which is on the cable network, e.g., video network, side performsoperations related to control channel signals communicated onout-of-band frequencies. The embedded conditional access (CA) module 326which includes decryption module 327 performs conditional accessdecryption for the cable, e.g., video side. The transcoding module 330converts between different formats used in cable devices to formats usedin IP devices, e.g., converting from an MPEG-2 format to an MPEG-4 orWindows Media format. In some embodiments, the transcoding module 330transcodes from an MPEG-2 Transport Stream (TS) or MPEG-4 part 10content from the cable head end to Digital Living Network Alliance(DLNA) codecs. The transrating module 332 cuts an input stream to alower bandwidth stream by performing re-encoding operations. In someembodiments, the power module 338 interfaces with and uses an externalsupply for power. In some embodiments, the power module 338 interfaceswith and uses a USB connection 304 to receive power. The authorizedservice domain (ASD) module 334 which includes encryption module 329performs encryption for re-encrypting into the ASD using an ASDprotocol. In various embodiments, a navigator resides on a renderingdevice, e.g., a user IP device such as a PC, and does not reside withinthe bridge device 300.

In some embodiments transcription is performed from traditionalconditional access (CA) technologies like PowerKey and/or Digicipher toin home Digital Rights Management (DRM), sometimes alternativelyreferred to as Digital Restrictions Management, or link protection suchas Digital Transmission Content Protection (DTCP) over IP or Windows DRMor Fairplay. In some such embodiments, the transcription is performed byCA module 326 working in coordination with ASD module 334.

Protocol conversion module 340 performs a protocol conversion between(i) a first protocol used by the cable network interface, e.g., aprotocol used for signals communicated through coax interface 310 whichis coupled to a cable network, and (ii) a second protocol used by asecond interface, the second protocol being different from the firstprotocol. The second interface, in bridge device 300 includes an MoCAinterface, USB interface, Ethernet interface, addition IP interfaces,and additional PC interfaces. The first protocol is, e.g., a cable modemprotocol and the second protocol is, e.g., an Ethernet protocolsupporting the communication of IP packets.

In one exemplary embodiment, the bridge device 300 includes embeddedsoftware, e.g., in memory 336 and/or resident in other modules which,when executed, e.g., by one or more of the microprocessors 328, performsat least some of the following functions and/or has the followingcharacteristics: routes MPEG2 transport streams to an IP network;includes sign-on capability to the cable network, e.g., video network;is field upgradeable; supports the Emergency Alert System (EAS), e.g.,SCTE18 EAS; provides a Universal Plug and Play (UPnP) server, andprovides a web server mechanism, accessible from the IP ports fordiagnostics and configuration. The UPnP server: (i) delivers video/audiotransport via UPnP AV, (ii) presents system channel line up, e.g.,provides content directory service; (iii) performs tuner resourcecommand and control, e.g., channel change, etc.; (iv) performs ASDfunctions including, e.g., authentication for cable distribution system(CDS) and PSP; (v) provides EAS services such as push alert and audiofiles and force tune event. Diagnostics included in the web servermechanism allow queering from the head end and on the customer side isimplemented as a Web page. Diagnostics include man machine interface(MMI) type diagnostics and IP diagnostics. The web server mechanism alsosupports IP configuration operations.

In accordance with a feature of some embodiments, content access atleast some of the IP devices is on a restricted basis. An authorizedservice domain (ASD) is constructed. An authorized service domainincludes a trusted domain. A trust relationship exists with devices,e.g., the IP devices, and the cable network, e.g., the video network,concerning access. In various embodiments, a key on the IP device, e.g.,PC is used for encryption and comes across with a private key forcontent.

Various bridge devices 300 are lower cost than full-fledged set-topboxes, as the bridge devices 300 do not typically include a videodecoder or cable card. Thus a single home can have multiple low costbridge devices 300 servicing a plurality of different IP based devicesat the customer premise.

Resource manager module 331 within the bridge device 300 handlesmultigroups and other content distribution functions. One or morestreams can be sent to each IP user device. In some cases, the streammay be a point to point stream to an individual IP device, e.g., inresponse to received channel and/or program request from an end user. Insome other cases, the stream may be a multicast stream available to aplurality of IP user devices, e.g., a plurality of IP devices coupled tothe same Ethernet or local area network.

Content routing module 333 performs routing of content and/or MPEG,e.g., MPEG-2 transport streams, information such as selected programinformation, to an IP network and/or particular IP device or devices.System information routing module 335 routes system information such asguide information and tier information from the cable network and/orhigh speed data network to the IP network, wireless network, and/orindividual IP device or devices. Program guide conversion module 337converts an electronic cable program guide, e.g., an electronic cableprogram guide formatted for use by a conventional cable system end userdevice, to a format which can be presented to an IP device.

FIG. 4 is a flowchart 400 of an exemplary method of operating a bridgedevice to provide content, e.g., video content from a cable network toan end user device. The bridge device is, e.g., exemplary bridge device300 of FIG. 3. In various embodiments, the bridging device does notinclude a video decoder for generating decoded video. Operation startsin step 402 where the bridge device is powered on and initialized andproceeds to step 404.

In step 404, the bridge device receives a signal from an end userdevice, the signal including information specifying a user selectedchannel. The end user device is, e.g., one of an IP device, a mediacapable device, a cell phone, a personal data assistant, and a personalcomputer. Then in step 406, the bridge device tunes a tuner included inthe bridge device to a channel specified by the end user device inresponse to the received signal from the end user device. In variousembodiments, the tuning involves selection of a QAM channel from among aplurality of alternative QAM channels. Operation proceeds from step 406to step 408.

In step 408, the bridge device receives video content, e.g., encryptedvideo content via a cable network, and in step 410 the bridge device isoperated to interface between the cable network and at least one of: i)a non-cable network and ii) an end user device. The non-cable networkis, e.g., one of an Ethernet and a wireless network, e.g. a WI-FInetwork. In some embodiments, the end user device is coupled to thebridging device via the non-cable network. Operation proceeds from step410 to step 420 and, in some embodiments, to one or more of steps 412,416 and 418.

In step 420, the bridge device performs communications layer protocoland/or signaling translations and/or conversions. For example, in step420 the bridging device performs a protocol conversion operation toconvert between a communications format used by the cable network and acommunications format used by the non-cable network. One exemplaryprotocol used by the cable network is a Transport layer protocol and oneexemplary protocol used by a non-cable network is Internet Protocol.Operation proceeds from step 420 to step 422.

Returning to step 412, in step 412 the bridge device decrypts encryptedvideo content received from the cable network. The decryption isperformed, e.g., by a conditional access module. Operation proceeds fromstep 412 to step 414, in which the bridge device re-encrypts thedecrypted video content using a different encryption method than wasused to encrypt the video content received from the cable network. There-encryption is performed, e.g., by an authorized service providermodule. In some embodiments transcription is performed from traditionalconditional access (CA) technologies like PowerKey and/or Digicipher toin home Digital Rights Management (DRM), sometimes alternativelyreferred to as Digital Restrictions Management, or link protection suchas Digital Transmission Content Protection (DTCP) over IP or Windows DRMor Fairplay. In some such embodiments, the transcription is performed bya CA module working in coordination with ASD module. Operation proceedsfrom step 414 to step 422.

Returning to step 416, in step 416, a transcoding module of the bridgedevice transcodes video content received from the cable network in afirst encoded format to produce video content in a second encodedformat, said second encoded format being different from the firstencoded format. In one example, the first format is a MPEG-2 formatwhile the second format is one of a MPEG-4 format and a Windows Mediaformat. In some embodiments, the transcoding module transcodes from anMPEG-2 Transport Stream (TS) or MPEG-4 part 10 content from the cablehead end to Digital Living Network Alliance (DLNA) codecs. In someembodiments, the transcoding of the video content produces a bitstreamhaving a lower data rate than the data rate of a first bitstreamincluding the received video content, the second bitstream beingcommunicated to the end user device. Operation proceeds from step 416 tostep 422.

Returning to step 418, in step 418 a transrating module of the bridgedevice performs a transrating operation to produce a second bitstreamhaving a lower data rate than the data rate of a first bitstreamincluding the received video content. Operation proceeds from step 418to step 422.

In step 422 the bridge device communicates encoded video data includingvideo content received from the cable network on the channel specifiedby the end user device to the end user device. In some embodiments, theencoded video content communicated to the end user device being anoutput of the re-encryption operation, an output of the transcodingoperation and/or an output of the transrating operation.

FIG. 5 is a flowchart 500 of an exemplary method of operating an enduser device in accordance with an exemplary embodiment of the presentinvention. The end user device is, e.g., one of: an IP device, a mediacapable device, a cell phone, a personal data assistant and a personalcomputer. Operation of the exemplary method starts in step 502 where theend user device is powered on and initialized and proceeds to step 504.In step 504, the end user device sends a signal to a bridge device, saidsignal including information specifying a user selected channel. Thebridge device is, e.g., a device which interfaces between a cablenetwork and at least one of: i) a non-cable network such as an Ethernetnetwork or a wireless communications network, e.g., a Wi-Fi network, andii) an end user device. In one example, where the bridge deviceinterfaces to the non-cable network, the end user device sends thesignal to the bridge device via the non-cable network. In anotherexample, the bridge device interfaces directly to the end user device,e.g., via a USB port connection.

Operation proceeds from step 504 to step 506. In step 506 the end userdevice receives signals including encoded video data including videocontent communicated from the cable network on the channel specified bythe end user device to the bridge device. The bridge device hasperformed processing of signals received from the cable network togenerate signals which are output from the bridge device directed towardthe end user device. In some embodiments, the end user device receivedsignals include re-encrypted video content which has been re-encryptedby the bridge device, where the encryption method used by the cablenetwork is different than the encryption method used by the bridgedevice. In some embodiments, the end user device received signalsinclude transcoded video content wherein the bridge device hastranscoded video content from the cable network which used a firstencoding format into a second encoding formati, which is different fromthe first encoding format. In some embodiments, the end user devicereceived signals include a second bitstream having a lower data ratethan a first bitstream received by the bridge device, wherein the secondbitstream was generated from the first bitstream by a transratingoperation performed by the bridge device. The end user device receivedsignals are communicated using a communications format used by thenon-cable network and/or user device, e.g., an IP format, while thesignals received by the bridge device from which the end user devicereceived signals are derived were communicated between the cable networkand the bridge device using a different format, e.g., a cable signalingtransport layer format, and the bridging device had performed a protocolconversion operation.

Operation proceeds from step 506 to step 508. In step 508 the end userdevice decodes the received encoded video data to recover video data. Insome embodiments a decryption operation is also performed as part of orin addition to step 508. Operation proceeds from step 508 to step 510 inwhich the end user device outputs the recovered video data to a displaydevice and/or displays the recovered video data.

FIG. 6 is a drawing 600 illustrates exemplary operations performed by abridge device 300 in accordance with an embodiment of the presentinventions. Cable modem data units 602 are received as input to thebridge device via a cable network interface. The received input 602 issubjected to a protocol conversion operation (part A), e.g., by aprotocol conversion module as indicated by box 604. The output of thepart A protocol conversion is recovered payload data 606, e.g., MPEG-2packets. The recovered payload data 606 is subjected to a decryptionoperation, e.g., by a conditional access module, as indicated by block608. Operation 608 results in decrypted recovered payload data units610.

A transcoding operation and/or transrating operation and/or packetizingoperation is perfomed on the decrypted recovered payload data units 610,e.g., by a transcoding module and/or transrating module as indicated byblock 612. This results in transcoded and/or transrated recoveredpayload data, e.g., IP packets with MPEG-4 payload 610. In variousembodiments, when transrating is performed the data rate of the outputbit stream is a reduced data rate with respect to an input bit stream.

Data 614 is subjected to an encryption operation, e.g., by an authorizedservice domain module using public/private keys as indicated by block616. The encryption operation of block 616 uses a different encryptionmethod than the encryption method used in generating cable modem packets602. The result of the encryption operation of block 616 is encryptedtranscoded and/or transrated recovered payload data, e.g., IP packetswith encrypted MPEG-4 payload.

Then, the data 618 is subjected to a protocol conversion operation (partB), e.g., by the protocol conversion module as indicated by block 620.This operation results in Ethernet frames, e.g., Ethernet framesincluding IP packets with encrypted MPEG-4 payload data 622, which iscommunicated via a secondary interface of the bridge device 300.

FIG. 7 is a drawing of an exemplary system 700 including a bridge device704 which performs transcoding and/or transrating operations inaccordance with the present invention. Exemplary system 700 alsoincludes a cable network 702, a set top box (STB) 708, user device 1 710and user device 712 coupled to the bridge device 704 via connections(716, 718, 720 and 722), respectively. Different interfaces may be, andsometimes are used for the different connections. In addition, system700 also includes a network storage device 706 coupled to the cablenetwork 702 via link 714.

Bridge device 702 supports transcoding and transrating between differententities including between different end user devices. Thus bridgedevice 702 serves as a bridge between connected devices, e.g., a PC anda PDA, allowing otherwise incompatible end user devices, which usedifferent formats, to communicate because the bridge device 702 performstrancoding and/or transrating operations. In addition, the bridge device702 can transcode/transrate content supplied by the cable network to theend user device. Different transcoding/transrating can be performeddepending on the different protocols, coding and/or data rates suppored,e.g., used by, the different possible source and destinations ofcontent.

Bridge device 704 includes a transcoding module 724, a transratingmodule 726, a backup module 728, and a device matching module 729. Insome, but not necessarily all embodiments, the bridge device 704 doesnot include a decoded video output which can be coupled directly to adisplay device. In such embodiments, the costs associated withsupporting a decoded video output and interface (including, e.g., plug)are avoided. Thus, even in some embodiments where transcoding issupported, a decoded video output may be omitted from the bridge device704. In one exemplary embodiment, bridge device 704 is used as thebridge device 300 of FIG. 3. In such an embodiment, transcoding module724 is transcoding module 330 of FIG. 3 and transrating module 726 istransrating module 332 of FIG. 3. In the FIG. 3 system ratedetermination module determines the data rate of content being or to besupplied to the bridge device 300 for delivery to another device as wellas data rates supported by the device to which the content is beingdelivered. Separate sub-modules may, and sometimes are, provided foreach of these rate determination functions. The determination of therate of content being or to be supplied to the bridge device may be madefrom stored information providing information about the rate used by thesource device and/or from analysis of the rate of actual contentreceived from the first device. Coding format determination module 344determines the coding format of content being supplied, or to besupplied, to the bridge device 300 for delivery to another device aswell as coding formats supported by the device to which the content isto be delivered. Separate sub-modules may, and sometimes are, providedfor each of these coding determination functions. The determination ofthe coding format of content being or to be supplied to the bridgedevice may be made from stored information providing information aboutthe coding format used by the source device and/or from analysis of thecoding format of actual content received from the source device. Thecoding formats supported by the device to which content is beingsupplied may be obtained from information stored in the bridge deviceindicating the destination device's capabilities. Recoding determinationmodule 346 determines when transcoding, transrating and/or bothtransrating and transcoding is to be performed. Recoding is to beperformed when the rate and/or coding of content being supplied by afirst device is does not match a rate and/or coding format supported bythe device to which the content is to be delivered. If the source deviceprovides the content in a coding format and at a rate supported by thedestination device, changes in the data rate and/or coding format neednot be made by the bridging device.

Transcoding module 724 converts between different formats, e.g., betweenan MPEG2 format and an MPEG4 format. The conversion may also be betweendifferent levels supported within a given coding format, e.g., between ahigh resolution level and lower or standard definition level or codingformat. Transrating module 726 is used to support changes in data ratesallowing the data rate of streamed content to be changed as it iscommunicated between different devices supporting, e.g., different datarates. The change in data rates may be implemented through the use ofencoding constraints and/or changes in the coding format used. Backupmodule 728 performs operations to store information, e.g., content beingcommunicated between different end user devices, in a network storagedevice, e.g., via a cable network connection. Thus, content beingsupplied to or from an end user device can be backed up prior to, orfollowing, transrating or transcoding thereby making it available fromthe network for later delivery to another device. Device matching module729 access stored memory in bridge device 704 associating differentdevices, e.g., by device ID or another identifier which may be includedwith supplied content or sent separately from content being supplied,with a set of information including format information, data rateinformation, and protocol information supported, e.g., used by, thedevice, and identifies the formats, data rates, and/or protocols used bythe individual device or devices. Device matching module 729 may includestored information indicating, in addition to individual end user devicecapabilities, information indicating what data rates/coding is to beused for pairs of end user devices communicating with one another and,optionally, what transcoding and/or transrating operation(s) are to bepreformed when two particular end user devices communicate. Whiletranscoding/transrating information for device pairs may be stored, itcan also be dynamically determined based on stored information about thecapability of the end user device to which content is being directed andfrom the characteristics of received content, e.g., data rate and/orcoding format, supplied by as source device, e.g., end user device ordevice on the cable network.

User device 1 710 is, e.g., a personal computer using MPEG2, while userdevice 2 712 is, e.g., a personal data assistant (PDA) using MPEG4.Arrow 730 illustrates that content, e.g., video and/or audio, from userdevice 1 710 which is in a first format and is communicated at a firstdata rate is sent to bridge device 704 which performs transcoding andtransrating resulting in content being conveying in a second format andat a second data rate to user device 2 712, wherein the first format isdifferent form the second format and the first data rate is differentfrom the second data rate. Arrow 732 illustrates that content, e.g.,video and/or audio, from user device 2 712 which is in the second formatand is communicated at the second data rate is sent to bridge device 704which performs transcoding and transrating resulting in content beingconveying in the first format and at the second data rate to user device1 710. Arrow 734 indicates that the bridge device 704 sends backup ofcontent communicated between the first and second devices (710, 712) viacable network 702 to network storage device 706. Note that thetranscoding/transrating of content communicated to the second end userdevice may, and often does, follow transcoding/transrating of contentsupplied from the cable network to the second end user device via thecable network and bridge device 704.

FIG. 8 is a flowchart 800 of an exemplary method of operating a bridgedevice, e.g., bridge device 700 of FIG. 7, in accordance with thepresent invention. Operation of the method starts in step 802 where thebridge device is powered on and initialized. Operation proceeds fromstart step 802 to step 804. In step 804, the bridge device determinesdata rate of the content supplied, or to be supplied, from a first enduser device, said determined data rate being a first data rate.Operation proceeds from step 804 to step 806. In step 806, the bridgedevice determines the coding format of the content supplied, or to besupplied, by the first end user, said determined coding format being afirst coding format. This may be done by analyzing content supplied tothe bridge device or by using stored information indicating the contentand/or data rate used by the device supplying the content. The operationproceeds from step 806 to step 808. In step 808, the bridge devicedetermines data rates supported by a second end user device to whichsaid content is to be supplied. Operation proceeds from step 808 to step810. In step 810, the bridge device determines coding formats supportedby the second end user device to which said content is to be supplied.Information about rates and/or formats supported by the second devicemay be, and sometime is, obtained by accessing stored informationindicating format(s)/rate(s) supported by the second end user device orby receiving information from the second end user device indicatingwhich formats it supports. The bridge device makes such determinations,e.g, the data rate and coding format being supported by the seconddevice, in order to determine if a transcoding operation and/or atransrating operation is needed. Following step 810, the operationproceeds from to step 812. In step 812, the bridge device receivessignals from the first end user device communicating content, e.g.,video and/or audio, using the first format and being communicated at thefirst data rate. Operation proceeds from step 812 to step 814. In step814, when the first format is not supported by the second end userdevice, the bridge device performs a transcoding operation changing theformat to a second format which is different from the first format, thesecond format being supported by the second end user device. Transcodingis performed in step 814 if the first format is supported by the seconddevice. Then in step 816, in cases where the first data rate is notsupported by the second end user device, the bridge device performs atransrating operation changing the data rate to a second data rate whichis different from the first data rate, the second data rate beingsupported by the second end user device. Transrating is skipped if thefirst data rate is supported by the second device. In some embodimentsthe transcoding and transrating are performed as part of a jointoperation in which steps 814 and 816 may be performed together, e.g., ina single re-coding operation. Operation proceeds from step 816 to step818 and, in some embodiments, from step 816 to step 820.

In step 818 the bridge device transmits output signals to the second enduser device said output signals conveying content communicated from thefirst end user device but using said second format and beingcommunicated at the second data rate. In step 820 the bridge devicetransmits a backup signal to a cable network for storage in a networkdevice, said backup signal conveying content received from said firstdevice and/or content transmitted to the second device.

In one exemplary embodiment, the bridge device is bridge device 704, thefirst user device is user device 1 710 which uses MPEG2, and the seconduser device is user device 2 712 which uses MPEG4. In some embodiments,the bridge device stores information associating different end userdevices with different formats, data rates and/or protocols. In somesuch embodiments, when one end user devices wishes to transmit contentto and/or receive content from another end user device, the bridgedevice accesses its stored information and identifies the formats, datarates and/or protocols used by the two end user devices and uses suchinformation to select the appropriate transcoding and/or transratingoperations.

While described in the context of a video system, it should beappreciated that the methods and apparatus of the present invention arenot limited to the delivery of video content via a cable network and canbe used to support delivery of audio content and/or other types ofinformation content via the cable network.

In various embodiments system elements described herein are implementedusing one or more modules which are used to perform the stepscorresponding to one or more methods of the present invention, forexample, receiving content, e.g., via a cable network, operating abridge device to interface, e.g., between a cable network and at leastone of a non-cable network and an end user device, tuning to a channelspecified by an end user device, operating the bridge device tocommunicated encoded content, performing a decryption operation,performing an encryption operation, performing a trancoding operation,performing a transrating operation, performing a protocol conversion,performing a backup storage operation, identifying a format, rate and/orprotocol associated with an end user device, etc. etc. Such modules maybe implemented using software, hardware or a combination of software andhardware. Each step may be performed by one or more different softwareinstructions executed by a processor, e.g., CPU.

At least one system implemented in accordance with the present inventionincludes a means for implementing each of the various steps which arepart of the methods of the present invention. Each means may be, e.g.,an instruction, processor, hardware circuit and/or combination ofelements used to implement a described step.

Many of the above described methods or method steps can be implementedusing machine executable instructions, such as software, included in amachine readable medium such as a memory device, e.g., RAM, floppy disk,etc. to control a machine, e.g., general purpose computer with orwithout additional hardware, to implement all or portions of the abovedescribed methods, e.g., in one or more nodes. Accordingly, among otherthings, the present invention is directed to a machine-readable mediumincluding machine executable instructions for causing a machine, e.g.,processor and associated hardware, to perform one or more of the stepsof the above-described method(s).

Numerous additional embodiments, within the scope of the presentinvention, will be apparent to those of ordinary skill in the art inview of the above description and the claims which follow.

What is claimed is:
 1. A method of operating a bridging device includinga tuner to provide content, comprising: receiving content via a cablenetwork; tuning to a channel specified by an end user device in responseto a signal from the end user device; interfacing between said cablenetwork and said end user device, said interfacing including: performinga transrating operation to produce a second bitstream having a lowerdata rate than the data rate of a first bitstream including the receivedvideo content; and communicating said second bitstream to the end userdevice, said second bitstream communicating encoded video data includingvideo content, received from the cable network on the channel specifiedby said end user device, to the end user device.
 2. The method of claim1, wherein said end user device is one of: an IP device, a media capabledevice, a cell phone, a personal data assistant, or a personal computer.3. The method of claim 1, wherein said end user device is coupled tosaid bridging device via a non-cable network; and wherein said non-cablenetwork is one of: an Ethernet or a wireless network.
 4. The method ofclaim 1, further comprising: prior to communicating said secondbitstream communicating encoded video data including video content tothe end user device: decrypting encrypted video content received fromthe cable network; and re-encrypting the decrypted video content using adifferent encryption method than was used to encrypt the video contentreceived from the cable network, said re-encrypted video contentincluding said encoded video data communicated to the end user device.5. The method of claim 1, further comprising: prior to communicatingsaid second bitstream communicating encoded video data including videocontent to the end user device: transcoding video content received fromthe cable network in a first encoded format to produce video content ina second encoded format, said second encoded format being different fromthe first encoded format, said encoded video data communicated to theend user device including content in said second encoded format.
 6. Amethod of operating a bridging device including a tuner to providecontent, comprising: receiving content via a cable network; tuning to achannel specified by a end user device in response to a signal from theend user device; interfacing between said cable network and at least oneof: i) a non-cable network or ii) said end user device; transcodingvideo content received from the cable network in a first encoded formatto produce video content in a second encoded format said second encodedformat being different from the first encoded format, said encoded videodata communicated to the end user device including content in saidsecond encoded format, said transcoding of the video content producing asecond bitstream having a lower data rate than the data rate of a firstbitstream including the received video content; and communicating saidsecond bitstream to the end user device, said second bitstreamcommunicating encoded video data including video content, received fromthe cable network on the channel specified by said end user device, tothe end user device.
 7. The method of claim 6, wherein said transcodingis performed as part of said interfacing operation.
 8. The method ofclaim 6, further comprising: performing a protocol conversion operationto convert between a communications format used by said cable networkand a communications format used by said non-cable network.
 9. A methodof operating a bridging device including a tuner to provide content,comprising: receiving content via a cable network; tuning to a channelspecified by an end user device in response to a signal from the enduser device; interfacing between said cable network and at least one of:i) a non-cable network or ii) said end user device; and wherein saidbridging device does not have a video decoder for generating decodedvideo.
 10. A method of operating a bridging device including a tuner toprovide content, comprising: receiving content via a cable network;tuning to a channel specified by an end user device in response to asignal from the end user device; interfacing between said cable networkand at least one of: i) a non-cable network or ii) said end user device;and wherein said bridging device does not have a decoded video output.11. The method of claim 1 further comprising: receiving content from afirst end user device; and processing the content from the first enduser device by performing at least one of: i) a transcoding or ii)transrating operation to generate processed content; and transmittingthe processed content to a second end user device.
 12. A method ofoperating a bridging device including a tuner to provide content,comprising: receiving content via a cable network; tuning to a channelspecified by an end user device in response to a signal from the enduser device; interfacing between said cable network and at least one of:i) a non-cable network or ii) said end user device; receiving contentfrom a first end user device; determining at least one of a data rateand coding format of content supplied by the first user device;processing the content from the first end user device by performing atleast one of: a transcoding or ii) transrating operation to generateprocessed content; and transmitting the processed content to a secondend user device; wherein transcoding is performed as part of saidprocessing when the coding format of content supplied by the first userdevice is different from a coding format supported by the second userdevice; and wherein transrating is performed as part of said processingwhen the data rate of content supplied by the first user device isdifferent from a data rate supported by the second user device.
 13. Abridging device, comprising: a cable network interface for receivingcontent via a cable network; a second interface for interfacing saidbridging device to at least one of i) a non-cable network or ii) an enduser device; a tuner module for tuning to a channel specified by saidend user device in response to a signal from the end user device; a ratedetermination module adapted to determine a data rate of contentsupplied by a first end user device; and a protocol conversion modulefor performing a protocol conversion between a first protocol used bysaid cable network interface and a second protocol used by said secondinterface, said second protocol being different from said firstprotocol.
 14. The bridging of claim 13, wherein said end user device isone of: an IP device, a media capable device, a cell phone, a personaldata assistant, or a personal computer.
 15. The bridging device of claim13, wherein said second interface interfaces said bridging device tosaid non-cable network, wherein said non-cable network is one of: anEthernet or a wireless network; wherein said end user device can becoupled to said bridging device via said non-cable network; and whereinsaid second interface includes at least one of a Media over CoaxAlliance interface module or an Ethernet Interface module.
 16. Thebridging device of claim 13, wherein said second interface interfacessaid bridging device to said end user device, and wherein said secondinterface includes at least one of a USB interface module, RS422interface module or RS232 interface module.
 17. The bridging device ofclaim 13, further comprising: a decryption module for decryptingencrypted video content received from the cable network; and anencryption module for re-encrypting the decrypted video content using adifferent encryption method than was used to encrypt the video contentreceived from the cable network, and wherein output of the encryptionmodule is communicated via the second interface.
 18. The bridging deviceof claim 13, further comprising: a transcoding module for transcodingvideo content received from the cable network in a first encoded formatto produce video content in a second encoded format, said second encodedformat being different from the first encoded format, and whereinencoded video data communicated to the end user device includes contentin said second encoded format.
 19. A bridging device, comprising: acable network interface for receiving content via a cable network; asecond interface for interfacing said bridging device to at least one ofi) a non-cable network or ii) an end user device; a tuner module fortuning to a channel specified by said end user device in response to asignal from the end user device; a protocol conversion module forperforming a protocol conversion between a first protocol used by saidcable network interface and a second protocol used by said secondinterface, said second protocol being different from said firstprotocol; a transcoding module for transcoding video content receivedfrom the cable network in a first encoded format to produce videocontent in a second encoded format, said second encoded format beingdifferent from the first encoded format, said transcoding moduleproducing a second bitstream having a lower data rate than the data rateof a first bitstream including the received video content, said secondbitstream being communicated to the end user device; and wherein saidsecond bitstream communicated to the end user device communicatesencoded video data including content in said second encoded format. 20.A bridging device, comprising: a cable network interface for receivingcontent via a cable network; a second interface for interfacing saidbridging device to an end user device, said second interface includingat least one of a USB interface module, RS422 interface module or RS232interface module; a tuner module for tuning to a channel specified bysaid end user device in response to a signal from the end user device; aprotocol conversion module for performing a protocol conversion betweena first protocol used by said cable network interface and a secondprotocol used by said second interface, said second protocol beingdifferent from said first protocol; and a transrating module forperforming a transrating operation to produce a second bitstream havinga lower data rate than the data rate of a first bitstream including thereceived video content, said second bitstream being communicated to theend user device.
 21. The bridging device of claim 13, wherein saidprotocol conversion module performs a protocol conversion operation toconvert between a communications format used by said cable network and acommunications format used by said non-cable network, and wherein saidcommunications format used by said cable network is a cable modemcommunications protocol format and wherein said communications formatused by said non-cable network is an Ethernet protocol format.
 22. Abridging device, comprising: a cable network interface for receivingcontent via a cable network; a second interface for interfacing saidbridging device to at least one of i) a non-cable network or ii) an enduser device; a tuner module for tuning to a channel specified by saidend user device in response to a signal from the end user device; aprotocol conversion module for performing a protocol conversion betweena first protocol used by said cable network interface and a secondprotocol used by said second interface, said second protocol beingdifferent from said first protocol; and wherein said bridging devicedoes not have a video decoder for generating decoded video.
 23. Abridging device, comprising: a cable network interface for receivingcontent via a cable network; a second interface for interfacing saidbridging device to at least one of i) a non-cable network and ii) an enduser device; a tuner module for tuning to a channel specified by saidend user device in response to a signal from the end user device; aprotocol conversion module for performing a protocol conversion betweena first protocol used by said cable network interface and a secondprotocol used by said second interface, said second protocol beingdifferent from said first protocol; and wherein said bridging devicedoes not have a decoded video output.
 24. The device of claim 13,further comprising: a coding format determination module adapted todetermine a coding format of content supplied by the first end userdevice.
 25. The device of claim 24, further comprising: a recodingdetermination module for determining, with regard to content supplied bythe first end user device to be communicated to a second end userdevice, i) if transrating is to be performed, ii) if transcoding is tobe performed and iii) if transrating and transcoding is to be performed.26. The method of claim 4, wherein said re-encryption is used fordigital rights management (DRM); and wherein the re-encryption operationuses encryption which depends on which end user the re-encrypted contentis to be delivered.